Fin tube unit with curled collar



May 21, 1968 w. RICHTER 3,384,168

FIN TUBE UNIT WITH CURLED COLLAR Filed Oct. 21, 1965 INVENTOR. Waher Richter ATTORNEY United States Patent 3,384,168 FIN TUBE UNIT WITH CURLED COLLAR Walter Richter, Syosset, N.Y., assignor to Hudson Machine & Tool Corporation, Farmingdale, N.Y. Filed Oct. 21, 1965, Ser. No. 500,129 2 (Ilaims. (Cl. 165-182) ABSTRACT 6F THE DISCLOSURE This invention is directed to a fin tube unit having an improved fin construction which is provided with a cylindrical collar portion circumscribing the opening formed in the fin for receiving the tube. The collar portion is specifically formed so as to function as a means for varying the spacing between adjacent fins depending upon particular design considerations. This is attained by providing the free end of the cylindrical collar portion with a curled end which is integrally formed with the collar portion about the entire periphery thereof, whereby the angular degree of the curl is utilized to vary the overall height of the collar to vary the spacings between adjacent fins accordingly. The curled collar is then secured in heat transfer relationship to the tube by an expanded frictional fit therebetween. To minimize the noise resulting from expansion and contraction of the fin tube unit during operation the fins are further provided with a track member secured to the aligned corner portions of the fins whereby the track element is specifically formed and constructed so as to define a line contact between the fins and their supporting brackets.

This invention relates in general to a fin tube unit, and more specifically, to a unit adapted for use as a baseboard radiation heating unit or the like. Such a fin tube unit is comprised essentially of an elongated tube having a plurality of radiating fins secured thereto in longitudinally spaced relationship therealong.

In the manufacture of such fin tube heat transfer units, adapted for heating and/or cooling, it is important that the fins be accurately spaced longitudinally of the tube carrying the heating and/ or cooling medium. For fin tube units constructed for application as for baseboard radiation or heating units, it has been discovered that the optimum spacing of the fins include 8 fins to 14 fins per inch; that is, a spacing between fins ranging from .125 to .071". Accordingly, it was heretofore customary to fabricate such fins with a central opening circumscribed by an integrally formed collar extending laterally therefrom, as for example, by a drawing operation. Thus, the practice was to draw the collar in forming the fin to substantially the height necessary to define the desired spacing between adjacent fins. As the die forming operation of the extruded collar always formed the collar of the same height, it was either necessary to utilize different dies to effect a change in the collar length of the fins, in the event the spacing between adjacent fins were desired to be varied; or to utilize an auxiliary means to change the collar height of a fin to obtain the desired range of spacings between fins for various design considerations.

Heretofore, the most common and expedient method for changing or varying the collar height of a fin in order to vary the longitudinal spacing of the fins along a given tubular member was to flare the outer end of the collar outwardly until the overall height of he straight portion of the collar plus the flare portion defined the proper overall height of the collar to give a desired spacing between fins along a tube. For example, if a fin having the unflared collar height of .145 was required to be spaced along a tube at spacings of .125 inch, the end of the collar had to be flared a predetermined amount. If this .145 collar height was flared outwardly so as to define an overall collar height of less than .091, i.e. to accommodate 11 fins 3,384,168 Patented May 21, 1968 per inch, the degree of flaring required was so acute that the collar would likely crack. If the collar cracked on flaring, such cracks usually propagated into the straight portion of the collar, thereby making that fin deficient in its heat transfer characteristics upon the expansion of the tube into the collar. Also, such cracking adversely affected the degree of attachment between the tube and the fin. As a result, it was heretofore customary to utilize a relatively large numb-er of different dies to construct fins adapted to be used in various design considerations. Consequently, collared fins utilized in fin tube units for heat transfer applications had to be independently formed on special dies for each run of units having different spacing requirements between adjacent fins.

Accordingly, it is an object of this invention to provide an improved fin construction having a collared opening which is uniquely shaped so as to enhance the strength thereof as well as the heat transfer characteristics thereof When such fins are secured to an elongated tube carrying a heating and/ or cooling medium therethrough.

It is another object of this invention to provide a fin tube unit comprised of an elongated tube and an improved fin having a curled collared opening whereby the spacing between adjacent fins can be varied as may be required by varying the degree of curl on the fin collar.

Another object of this invention is to provide a fin construction having a collar of predetermined height about an opening therein which may be varied within a given range to accommodate for various fin spacings along a tube adapted to be received in the opening thereof.

Another object of this invention is to provide a fin tube unit having an improved fin construction formed with a collared opening in which the free end of the collar is circumscribed by a curl which can be varied so as to ad just the overall height of the collar for specific design appli cations.

The foregoing objects and other features and advantages are attained in a fin tube unit comprised of an elongated tube and a plurality of fins secured thereto at regularly spaced intervals therealong. Each fin is formed with a collar opening through which the tube and the collar can function to define the spacing between adjacent fins. In accordance with this invention, a curl is integrally formed about the periphery of the collar to define a circumscribing bead whereby the overall strength of the collar is enhanced and whereby the effective height of the collar can be varied according to the degree of curl thereby. The curl collar is secured in heat transfer relationship to the tube by means of an expanded fit therebetween.

To accommodate for the problem of expansion and retraction and of minimizing the noise resulting therefrom, an elongated track member formed of a suitable flexible and preferably, non-metallic material, is f-rictionally secured to the aligned corner portions of the successive fins. Essentially the track member comprises a member having a pair of angularly disposed leg portions forming therebetween an angle which is fitted to the corner of the fins to protect them. The opposed free edges of the track are formed with an inwardly turned bead. In assembly, the track member is simply snapped in place over the respective aligned corner portions of the fins.

A feature of this invention resides in the provision of a fin having a collared hole with a reversely bent curl circumscribing the periphery thereof to enhance the strength of the collar as well as providing a means whereby its effective overall length or height can be varied to accommodate varying spacing between adjacent fins as may be required in particular design applications.

Another feature of this invention is to provide a fin construction having a curl collar adapted to be secured to a tube by an expanded fit therebetween.

Another feature resides in the provision of a fin construction having a curled collar circumscribing the opening to which the tube carrying the heating medium is expanded to enhance the heat transfer relationship or characteristics therebetween.

Other features and advantages will become more readily apparent when considered in view of the drawings and specification in which,

FIGURE 1 illustrates a plan view of the improved fin construction of this invention.

FIGURE 2 is a sectional view taken along line 22 of FIG. 1.

FIGURE 3 is 'a side elevation View illustrating a segmental portion of a fin tube unit utilizing the fin construction of FIGS. 1 and 2.

FIGURE 4 is a sectional view of a fin construction illustrating a collar formed with a full curl.

Referring to the drawings, there is shown in FIG. 3 a fin tube unit It constructed in accordance with the instant invention. The fin tube unit of the type disclosed is readily adapted for use, as for example, as a radiation unit in a baseboard heating installation.

The fin tube unit comprises essentially an elongated tube 11 through which a heating medium flows. A plurality of substantially rectangularly formed fins 12 are secured at longitudinally spaced intervals along the tube 11 in heat transfer relationship. Generally, the installation of such fin tube units 10 includes the utilization of supporting brackets or elements 13 upon which a length of fin tube unit 10 is supported. Generally, such brackets or supports 13 comprise an arm 14 adapted to be connected to a wall 15 and a laterally extending arm portion 16 to form the support on which the fin tube unit 10 is placed. Accordingly, a plurality of such supports 13 are longitudinally spaced along a suitable supporting Wall 15 to provide the necessary points of support for the elongated fin tube unit 10.

As shown, the respective fins 12 spaced along the tube are substantially rectangular in shape and each is provided with a central opening 17 adapted to receive the tube 11 of the unit. Usually such fins are formed of sheet aluminum, copper or the like. As best seen in FIGS. 1 to 3, a collar 18 extending laterally of the fin circumsc-ribes the central opening 17.

In accordance with this invention, the free end of the collar 18 terminates in a reverse fold or curl 19 which may be defined as either a partial curl (FIG. 2) or full curl (FIG. 4) depending upon the effective length or height h of the collar desired for a particular disposed unit. Accordingly, as seen in FIG. 3, the collar height It so formed defines a spacing between adjacent fins 12 when a plurality of such fins are secured to a tube. With the construction of the curl collar fin described, it will be noted that the etfective length or height h can be varied depending upon the degree or amount of curl. Accordingly, the spacing between adjacent fins 12 can be varied as desired for a given design consideration during the forming of the die, as more particularly described in a copending application, Ser. No. 500,130, filed Oct. 21, 1965. The curl end 19 thus described allows the ends of the collar to form between extreme limits without cracking which will be propagated into the straights 19A thereof, and thereby adversely effect the heat transfer characteristics thereof and/ or the bond or attachment between the tube 11 and the fins 12. Also the circumscribing curl 19 about the free end of the collar enhances the overall strength of the collar, permitting a more positive attachment as the tube is expanded to the fin. For an apparatus capable for constructing the curled collar, reference is made to a co-pending patent application, Ser. No. 500,130, filed Oct. 21, 1965.

In an effort to minimize noise due to expansion and contraction of. the heating unit when placed in operation, a track may be extended along the aligned corner portions of the fins. As shown, each corner 22 of the fin is defined by a point between a pair of adjacent side edges disposed at substantially right angles with respect to one another. The side edges of the fins adjacent the respective corners thereof are each provided with a notch 23. Accordingly, the notch 23 defines a corner having a reduced neck portion 24 by which the respective corners of the fins are integrally connected to the main body of the fin, and thus defining barbs 25 adjacent the corners or points of the fin.

The track 21 comp-rising an elongated member is extended along the respective corner portions of the fin to form a protective cover therefor and to define the area of contact between the fin tube unit 10 and its supporting bracket 16. The track member 21 may be formed of any suitable flexible or non-metallic material, as for example, a suitable plastic or the like. As shown, the opposed leg portions 21A, 21B of the track define therebetween an acute angle which is less than the angle defined between the adjacent side edges of the corners.

The free ends of the opposed leg portions 21A, 21B of the track member 21 are each provided with an inwardly turned beaded edge portion 26. The arrangement is such that the beaded edge portion 26 of the track 21 when assembled to the fins, are adapted to be snapped into the aligned notches 23 adjacent the corner of the fin. Because the angle defined between the opposed leg portions 21A, 21B of the track member 21 is less than the angle defined by the sides of the corner points, the arrangement is such that the barbs 25 will penetrate the head 26 of the track member. Also, because the angle of the track member is less than that of the corner points, the legs of the track member will tend to deform so that the apex 27 of the track 21 extends beyond the apex of the corner. The apex 27 thus defines a line contact with the supporting bracket 16 when the track fin tube unit is supported thereon. Accordingly, the fin tube unit throughout its entire length is supported on the respective brackets or support elements 16 by a pair of spaced apart line contacts. With the fin tube unit 10 thus supported, a minimum of resistance is offered between the fin tube unit 10 and the support 16 thereof during expansion and contraction. Accordingly, the amount of resistance and noise resulting therefrom is reduced to a minimum. Also because the edges of the notches or barbs 25 penetrate the inner surface of the track 21, the track is positively secured to the fins at spaced intervals therealong. The edges of the corners embedded in the track protect the same from becoming bent or distorted. As the track is formed of a suitable plastic material, it will silence or dampen any sound or noise which would otherwise result from any relevant movement between the fin tube unit and the supporting bracket.

While the instant invention has been described with reference to a particular embodiment thereof, it will be readily appreciated and understood that variations and modifications may be made without departing from the spirit or scope of the invention.

What is claimed is:

1. A fin tube unit comprising,

(a) an elongated tube,

(b) a plurality of fins longitudinally spaced along said tube at predetermined intervals,

(c) each of said fins having a central opening for receiving said tube,

(d) an integrally formed laterally extending cylindrical collar portion cireumscribing said opening whereby said collar defines the said predetermined longitudinal spacing between adjacent fins in said tube,

(e) said collar having its free end reversely bent to define a spiral curl substantially curved upon itself eircumscribing the periphery thereof to enhance the strength thereof and whereby the angular degree of said curl varies the spacing between adjacent fins,

(f) an expanded fit between said tube and the curled collar of said fins for securing the fins to said tube.

5 6 2. In a fin tube unit comprising an elongated tube and an expandable fit between said tube and the curled and a plurality of similarly constructed fins spaced at collar for securing the fin to said tube. predetermined intervals along the length of said tube, the improvement wherein, References Cited each of said fins has a central opening through which 5 UNITED STATES PATENTS said'wbfl extends, 2,245,069 6/1941 Clarke 165-181 an integrally formed collar circumscribing the open- 2 731 245 1 195 ,McChesney 113 .11 ing of each fin whereby said collar defines said pre- 2,963,276 12/1960 N l 165 66 X determined longitudinal spacing between adjacent 3,258,066 5/1966 Becher et a1. 16555 fins spaced along said tube, 10 3,266,563 8/ 1966 Sinclair 16555 X each of said collars terminating in a curl circumscrib- 2,053, 9/ 9 Forr r et al. 165-181 ing the periphery of said collar whereby the free 3, 9, 08 6/ 967 N lson 16555 X end of said curl is reversely bent and spirally curved FOREIGN PATENTS upon ltself to vary the angular degree of sad curl 15 1,168 1913 Great Britain.

so that the overall height of said collar is rendered variably proportional to the angular degree of said ROBERT OLEARY, Primary Examiner.

curl and whereby the strength of said collar is proportionally enhanced in accordance with the angular EDWARD MICHAEL Exammer' degree of said curl, 20 T. W. STREULE, Assistant Examiner. 

